Patent GB-190407562-A (GB)
Title: Improvements in or relating to Arc Lamps.
Inventor: NOMDEDEU CHARLES
Filed: 1904-03-30
Granted: 1904-09-22
Abstract: 7562. Nomdedeu, C. April 11, A.D. 1903, [date applied for under Patents Act, A.D. 1901]. Arc lamps in which the distance between the carbons is regulated by electro-thermic action. In the lamp shown in Fig. 1, the terminal 1 is connected to the upper end of a wire 9 stretched in the hollow tube 4, and the lower end of which is connected to the lower carbon 12. The upper end is fastened to one end of a pivoted lever 7, to the opposite end of which is attached a spring 37 fastened to the bottom flange of a central fixed pneumatic cylinder 23. The piston 24 carries a metal tube casing 19, in which the upper carbon 18 is mounted, and which slides in the guide-sleeve 20. A wire 41 connects the terminal 2 to a spring blade 27, fixed by an adjustable lug to the casing 19, and provided, with a fork 29 carrying the spindle of a roller 30, which engages through an opening in the tube 19 with the upper carbon 18. When the circuit is closed, the expansion of the wire 9, due to the large current, allows the lever 7 to turn and, under the action of the spring 37, to depress a rod 35, which slides in the hollow tube 5 and is hinged to the lever 33. The other insulated end 32 of this lever raises the arm 31 of the fork 29, and a slight wedging of the carbon between the roller 30 and the tube 19 takes place, the carbon 18 rising to a suitable extent. As the arc becomes longer, the current strength decreases and the wire 9 contracts, turning the lever 7 against the action of the spring 37. The pressure of the end 32 on the arm 31 is thus relieved, and the piston 24 descends slowly under its own weight with that of the tube 19 and carbon 18 till the latter has been brought sufficiently near the lower carbon, when the current increases and the wire 9 again expands. This brings the lever 33 again into action, and the downward motion is stopped by the wedging of the roller 30. In a differential lamp, Fig. 2, two stretched wires 46, 47 are provided in the tubes 44, 45, and their upper ends are connected respectively to the pivoted levers 48, 49. A fixed fork or bracket 52 carries the spindle of a grooved pulley, and the depending levers 54 carry a pin 55, about which can oscillate a pawl device or shoe 56 adapted when operated to engage the pulley 53. A rod 57 connects the pawl 56 to the depending arm 58 of the lever 48. The carbon-holders 61, 62 are suspended from the pulley by a string 63 and slide on the rods 46, 47. The carbon electrodes are connected to the terminals 70, 43, and a shunt circuit is provided between the terminal 70 and the terminal 43 through the stretched wire 47 and a resistance coil 78<a>. Initially the carbons are in contact, and, when the current passes, the wire 46 expands and enables the lever 48 to pivot under the action of the spring 59 ; the movement of the rod 57 causes the pawl 56 to move the pulley, and as a result the carbons are separated. A current will also pass through the shunt wire 47, which expands, and the depending arm 65 of the lever 49 soon comes into contact with the terminal 64, which short-circuits the wire 46 through the wires 72, 73, 79. As the wire 46 cools, the lever 48 is pulled over against the action of the spring 59, and, after passing through its normal position, the pawl 56 turns the pulley in the other direction so as to bring the carbons nearer together. Also, when the wire 46 is short-circuited, the current in the wire 47 decreases, and the contraction of this wire causes the lever 49 to turn under the action of a spring similar to the spring 59 but on the other side of the pulley. The arm 65 is thereby moved, and breaks the contact with the terminal 64, after which the main current again flows through the resistance wire 46. The regulation will continue by a series of similar oscillations of the levers 48, 49 and the pawl 56 moving the pulley at suitable moments.